iomux-v3: Place pad control definitions into common file

Instead of having the same PAD control definition in each MX6 variant pin file,
place it into a common location.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
mx6: Add solo-lite variant support

mx6 solo-lite is another member of the mx6 series.

For more information about mx6 solo-lite, please visit:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=i.MX6SL&nodeId=018rH3ZrDRB24A

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
mx6sl: Add initial support for mx6slevk board

mx6slevk board is a development board from Freescale based on the mx6 solo-lite
processor.

For details about mx6slevk, please refer to:
http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=IMX6SLEVK&parentCode=i.MX6SL&fpsp=1

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
mx6slevk: Change default environment to cope with OE changes

OpenEmbedded has change partitioning layout of generated image so it
does not raise warnings during the boot regarding unkown partition
being used for U-Boot.

Signed-off-by: Otavio Salvador <otavio@ossystems.com.br>